Multiple stop device for press brakes and the like



Jan. 12, 1965 M. w. HAZELTON ETAL 3,165,140

MULTIPLE STOP DEVICE FOR PRESS BRAKES AND THE LIKE Filed July 19, 1961 3Sheets-Sheet 1 INVENTORS u 0 F: k N mnw END Z N RAE mwq. r 8 W1 n m d mR m M .C A Y B .m 1 6 8 .1

1965 M. w. HAZELTON ETAL 3,

MULTIPLE STOP DEVICE FOR PRESS BRAKES AND THE LIKE Filed July 19. 1961 3Sheets-Sheet 2 INVENTOR. MERRILL W. HAZEL'I'ON, JOHN J. ERHART AND BYCARL J. Os-rennolzF,

6w 4 ATTORNEYS.

Jan. 12, 1965 M. w. HAZELTON ETAL 3,165,140

MULTIPLE STOP DEVICE FOR PRESS BRAKES AND THE LIKE Filed July 19. 1961 3Sheets-Sheet s BY CARLJ- OsreuooRF,

ATTORNEYS United States Patent hit) Fiied Italy 19, 1961, Ser. No.125,204 8 Ciaims. (Cl. 153-121) This invention relates to a multiplestop device for press brakes and the like wherein it is desired to perform on a press brake a series of bending operations wherein thematerial is to be bent to a different degree at each operation.

In a press brake, the amount of bend produced in a single operation ofthe ram can be accurately determined by the depth to which the upper diesecured to the ram enters into the lower die fixed upon the bed. If asingle piece of sheetmetal is to receive a plurality of bends ofdifferent angularities, it is desirable to provide an arrangement inaccordance with which the ram of the press brake would move downwarddifferent amounts on successive strokes. It would then also be desirablethat the machine have automatic means whereby such a particular cycle ofstrokes could be repeated so that if a large number of workpieces are tobe given a series of bends of varying degrees, the cycle which wouldcomplete one workpiece could be automatically repeated without anadjustment for additional workpieces.

In an operation such as has been outlined above, it is also desirablethat compensation may be made for small diiferences in gauge of thepieces being worked upon without disturbing the relationship between thevarious depths of stroke.

It is also highly desirable that the apparatus be capable of setting torepeat a cycle of any desired number of strokes and to indicate at anytime which stroke of the cycle will be carried out on the next operationof the machine. 7

It is also desirable that for one reason or another the operator be ableto cause the machine to skip a particular stroke in a cycle.

Accordingly, it is the general object of the present invention toprovide apparatus in a press brake and the like which will accomplishthe various desired features generally described above. It is anotherobject to provide apparatus which is relatively simple and which may beinstalled on an existing machine or built into a new machine.

These and other objects of the invention which will be described in moredetail hereinafter or which will be apparent to one skilled in the artupon reading the specifications, we accomplish by that certainconstruction and arrangement of parts of which we shall now describe anexemplary embodiment.

Reference is made to the drawings forming a part hereof and in which: 7

FIGURE 1 is a fragmentary perspective view of a typical press brakeshowing the general location of the apparatus of the present invention.

FIGURE 2 is a fragmentary elevational view of the portion of theapparatus as seen from the near end of the perspective view of FIGURE 1.

FIGURE 3 is a fragmentary elevational view as-seen from the right ofFIGURE 2'." 1

FIGURE 4 is a fragmentary wiring diagram.

FIGURE 5 is a front elevational view of the control box.

FIGURE 6 is a fragmentary Wiring diagram of another portion of theapparatus; and I aiaise Patented Jan. 12, I965 FIGURE 7 is a generalwiring diagram showing manual operation.

I In a copending application of Hazelton and Ostendorf, Serial No.784,499 filed January 2, 1959, and now Patent No. 3,041,963, andcopending herewith, there is dis closed a stop device for press brakesand the like. It is one of the features of the disclosure of saidapplication that a stop device is mounted to the bed of the brake and alimit switch is mounted on the ram so that when the ram descends, thelimit switch abuts the stop and terminates the downward movement of theram. The stop member is adjustable very accurately by means of a handwheel, at the front of the machine having associated therewith acounter-device calibrated in thousandths of an inch. In this way, thedepth of movement of the ram may be accurately controlled.

According to the present invention, we mount on the member whichconstitutes the bottom stop in said copending application, a pluralityof additional stop members which are individually capable of adjustmentwith respect to said member. These stop members may be micrometer typeadjustments and we mount upon the ram an equal number of limit switchesarranged to be actuated respectively by contact with the variousadditional stop members. In this way the additional stop members may beindividually adjusted with great accuracy with respect to the built-instop and yet the built-in stop and the additional stop members may allbe adjusted as a unit without disturbing the relationship between them.

We provide for manual operation whereby the operator may select anyparticular one of the preset stops for use on any stroke of the machineand we also provide for cyclic operation by means of a multiwaferstepping device.

Referring now in more detail to the drawings, we have shown in FIGURE 1a press brake having a bed 10 and side frames of which the near sideframe is indicated at 11. Each of the side frames carries ways uponwhich a ram 12 is arranged to be reciprocated. The ram is preferablyoperated by hydraulic power. In the copending application above referredto, and to which reference is made for a' fuller understanding of thebasic stop arrangement, we secure to the bed 16 a plate 13 which isparallel to but independent of the side frame 11. On the plate 13 ismounted a gear box 14 containing a pair of bevel gears, one of which isrotated by means of a shaft 15 from the front of the machine by rotationof a hand wheel 16. Rotation of the hand wheel 16 is transmitted throughthe gearing in the box 14 to a vertical shaft 17 which has a threadedportion engaging the stop member 18. The shaft 1% is stationary andpasses through a hole in the member 18 to prevent rotation of the member18 when the shaft 17 is rotated, so that the movement of the member 13upon rotation of the shaft 17 is only upward or downward.

Within the casing element 20 at the front of the machine is anindicating device which may be calibrated in thousandths of an inch bymeans of which the stop 18 can be very accurately adjusted.

The ram has secured to it a member 21 which houses a limit switchadapted to be engaged by contact with the stop member 18. This limitswitch is shown in FIG- URE 3 and 22.

According to the present invention, we secure to the member 18 amounting member 23 and upon the member 23 we mount an additional numberof stop elements, each of which is individually adjustable. In thefigures We have illustrated three such stop members at 24, 25 and 26. At27, 28 and 29 we have indicated conventional micrometer barrels by meansof which the stop elements 24, 25 and 25 respectively may be raised andlowered by very accurately measured amounts. The mircrometer adjustments27, 28 and 29 will be calibrated in thousandths of an inch.

We associate with the limit switch 22 additional limit switches 30, 31and 32 which will move with the ram. These are also contained within thecasing member 21. A spring member is associated with each of the stopmembers 24, 25 and 26 as shown, so that after contact is made with thestop member which extends farthest upward, it and other stop members canbe depressed without damage until the lowermost stop member actuatesthose respective limit switches to stop downward movement of the ram.

Other portions of the apparatus which appear in the figures do notpertain to the present invention and need not be described. For furtherdescription of such elements, reference may be had to the copendingapplication, Serial No. 784,499, referred to above.

Manual operation of the device is achieved very simply as indicated inthe diagram of FIGURE 7, wherein the same numbers as used in FIGURES 1to 3 inclusive have been applied to the various switches. Assuming firstthat the main bottom stop 13 has been adjusted for the deepestpenetration of the dies upon movement of the ram, the remaining bottomstops are adjusted for other depths which may be required. It will beclear from FIGURE '7 that the operator may simply manually actuate anyone of the four switches 22, 39, 31 or 32 to place it in operativecondition to stop the ram after it has been started by means of the footswitch 33.

For automatic operation, the device is, of necessity, more complex. inFlGURE we have illustrated the control panel. At 34 there is indicated aswitch having two positions, one of which is manual and the other ofwhich is automatic. At 35 we have illustrated a cycle switch which canbe placed in an indexed position to provide for a cycle of two, three orfour strokes. At 36 there is shown a pushbut-ton switch which has apurpose of advancing a cycle as will be described in more detailhereinafter;

.is a four gang switch. The various positions of the gang switch 35 areindicated in FIGURE 4 at 35a, 35b, 35c and 35d. The indicator 41 isshown in FIGURE 6. The automatic operation is achieved by means of astepping relay of which the coil is shown at 42. The stepping relayhasfour decks, all of which step as a unit under the influence of thecoil 4.2 and these decks are indicated at 'W, X, Y and Z. At the lefthand end of FIGURE 4 there is illustrated in conventional manner themanualautomatic switch 34. For manual operation the contactor 43 isclosed as indicated by the star under the letter M and for automaticoperation the contactor 44 is closed as indicatedby the star under theletter A.

The operation of a stepping relay is not a part of this invention and iswell known so that a detailed description thereof is thought to beunnecessary. Because there are in the illustnated embodiment a maximumof four strokes in the cycle and because the particular stepping relaywe had available had 11 steps, it will be observed that steps 5 through11 are shorted out by means of the conductor 45. Similarly, in deck Xconnections for posi tions 5 to Hare shorted out. In decks W and Z thishas not been done because as will clearly appear it is unnecessary tothe functioning of the apparatus. At 46 2- associated with the deck Ythere is a conventional home contact and at :7 there is il ustrated ajumper between interrupter contact 58 which is normally closed and ahome contact which is normally open. A similar interrupter is shown atSt? associated with deck W and this functions as a holding circuitduring stepping and homing operations. The advance cycle contaclor isshown at 35 and the contactors operated by the automatic down relay andwhich are normally closed are indicated at 51. it is believed that theoperation of the device may now be understood. An automatic down relay(not a part of the present invention but described and disclosed in saidcopending application) controls the switch Ell of FIG- URE 4 in thatwhen the ram reaches the top 0? its stroke and actuates a suitable toplimit switch, an automatic down relay is energized and this causes thecontactor El to open. The contactor 51 remains open during the downstroke of the ram but is deenergized when the bottom limit switch isactuated. When the bottom limit switch is actuated the contacor 51 againcloses and it is the closing of the contactor Ell which energizes thecoil 42 to actuate the stepping relay. Thus, when the ram reaches thebottom of its stroke, the stepping relay is energized and produces astepping of all of decks W, X, Y and Z. hen the coil 42 is energized.the contactor d9 closes and it remains closed until the interrupter d8opens, which takes place each time the coil 42 is energized. Theinterrupter 48 recloses and the coil 42 is deencrgized.

Assuming now that the apparatus is set up to perform an automatic cycleof four strokes and that these strokes are to be performed in the orderA, B, C, D, the switch 37 will be set for A, the switch 33 will be setfor B, the switch 3) will be set for C and the switch ill will be setfor D. Stroke A will be controlled by the limit switch 22, B by thelimit switch 3%, C by the limit switch 31 and D by the limit switch 32.It will be clear that on the next stroke of the ram, the coil 52 of thestepping relay will cause the stepping relay to advance to the number 2position. This will establish a circuit through deck W, switch atposition B through the switch 3% which will be placed in position to beactuated by its corresponding bottom stop 24.

On the next operation, the stepping relay will have advanced to position3 whereupon a circuit is established through deck W. switch 39 atposition C to place switch 31 in the circuit. On the next step, atposition 4, a circuit will be established through deck W to switch ll atthe D position, thus placing switch 32 in operative relation to thecircuit.

On the next operation of the relay when it advances to position 5, thedecks X and Y are provided to provide it with the jumper from steps 5through ll, whereby to cause the stepping relay to home and return tothe one position so that on the next operation a circuit will heestablished through deck W, switch 37 at position A to place the basiclimit switch 22 in the circuit.

It will be observed that deck Z is connected to the visual indicatorwhich is provided with matrices of bulbs to indicate visually thenumerals l, 2, 3 or 4, and because these require a higher voltage, thiscircuit is fed through a transformer 52 which converts the standardvolts A.C. to 220 volts. Deck Z of course is a part of the four deckstepping relay which has been described.

It the switch 35 is positioned at either position number 2 or 3 toprovide with a two stroke cycle or three stroke cycle operation, it willbe clear that the four gang cycle switch 35a, 35b, 35c, 35d will shortout the additional steps of the stepping relay to cause it to home aftertwo steps or three steps respectively.

If the apparatus is set up, for example, to perform a four stroke cycleand the fourth step is indicated at 41 to be the next stroke to beperformed, if the operator desires to skip one or more succeedingstrokes he may accomplish this by actuating the contactor 35 whichmanually performs the same function which is automatically performed bythe contactor 51. In other words, this energizes the coil 42 of thestepping relay causing it to advance to the next step. In the particularinstances described, this would cause the stepping relay to home andreturn to the number 1 position and the numeral 1 would then appear at41.

It will be clear that the limit switch 22 is the normal built-in bottomlimit switch disclosed in the copending application referred to andwhich is adjusable from the front of the machine by the hand wheel 16.The switches 3t 31 and 32 are all adjustable in relation to each otherand to the switch 22. After all of these switches are adjusted, they maythen be moved as a unit by the hand wheel 16 without disturbing therelationship between them so that if a piece or" metal, which is, forexample, .002 inch thicker than the previous piece, is to be put throughthe bending operations, the hand wheel may be adjusted to raise themembers 18 and 23 by .002 inch without disturbing the relationshipbetween the switches 22, 30, 31 and 32.

From the foregoing description, it will be seen that we have provided avery versatile arrangement for use with press brakes and the like and itwill be clear that while we have disclosed three additional adjustablestops and corresponding limit switches, this is not to be considered asa limitation upon the invention. Any desired number of limit switchesand botom stops may thus be provided within the limitation of the numberof steps available on the stepping relay. It will also be clear thatminor modifications of various kinds can be made without in the leastdeparting from the spirit of the invention. We therefore do not intendto limit ourselves otherwise than as set forth in the claims whichfollow.

Having now fully described the invention, what we claim as new anddesire to secure by Letters Patent is:

1. In a press brake and the like having a bed and a ram reciprocablewith respect to said bed; a bottom limit switch, and a member carrying abottom stop, one of said switch and member being mounted on said bed andthe other on said ram, and said member being adjustable to determine thepoint at which said bottom limit switch is actuated by said bottom stopto stop downward move ment of said ram, a plurality of additional bottomlimit switches mounted adjacent said first mentioned limit switch, and aplurality of additional bottom stops mounted on said member, each ofsaid additional bottom stops being adjustable with respect to saidmember, and an operative electric circuit including switch means forplacing any and all of said limit switches selectively into operativerelation to said circuit, and means for rendering said selected limitswitches operative in any sequence responsive to successive strokes ofsaid ram to provide a cycle of operation wherein the downward movementof said ram'is stopped at difierent points on successive strokes in saidcycle, whereby all of said bottom stops may be adjusted as a unit tocompensate for variations in thickness of the material being operatedupon, without disturbing the settings of said stops in relation to eachother.

2. A structure according to claim 1, wherein means are provided forselecting the number of strokes of said ram to constitute said cycle.

3. A structure according to claim 2, wherein visual means are providedto indicate at any time the number of the stroke in said cycle whichwill be constiuted by the next stroke of said ram.

4. The structure of claim 3, wherein means are provided for passing overany desired number of strokes in said cycle.

5. A structure according to claim 1, wherein said operative electriccircuit and said means comprise a number of selector switches equal to amaximum number of strokes per cycle, each of said switches having anumber of selection positions equal to the number of said limitswitches, a stepping relay, means for energizing said stepping relay ateach stroke of said 1am, said stepping relay arranged to place saidselector switches in an operative circuit one for each step in sequence,a number of operative circuits each including one selector switch andselectively any of said limit switches, whereby when a selector switchis energized one of said limit switches is placed in operative relationto said circuit.

6. A structure according to claim 5, wherein means are provided to causesaid stepping relay to home after any desired number of strokes of theram less than the maximum number of strokes per cycle.

7. A structure according to claim 6, wherein a series of numeralindications, one for each stroke of said maximum number of strokes percycle are provided, and wherein operative connections are providedbetween said stepping relay and said series to cause one of said seriesof numeral indications to indicate after each stroke of said ram thenumber of the next stroke in said cycle.

8. A structure according to claim 7, wherein a manually operated switchis provided to energize said stepping relay without operation of saidram, to pass over any desired stroke of said cycle.

References Cited by the Examiner UNITED STATES PATENTS 2,543,759 3/51Cannon et a1. 1532l 2,797,724 7/57 Walldow 15321 2,837,928 6/58 Meredith15333 2,840,135 6/58 Fowler 153-21 3,044,289 7/62 Rexford -256 XRCHARLES W. LANHAM, Primary Examiner. WILLIAM J. STEPHENSON, Examiner.

1. IN A PRESS BRAKE AND THE LIKE HAVING A BED AND A RAM RECIPROCABLEWITH RESPECT TO SAID BED; A BOTTOM LIMIT SWITCH, AND A MEMBER CARRYING ABOTTOM STOP, ONE OF SAID SWITCH AND MEMBER BEING MOUNTED ON SAID BED ANDTHE OTHER ON SAID RAM, AND SAID MEMBER BEING ADJUSTABLE TO DETERMINE THEPOINT AT WHICH SAID BOTTOM LIMIT SWITCH IS ACTUATED BY SAID BOTTOM STOPTO STOP DOWNWARD MOVEMENT OF SAIR RAM, A PLURALITY OF ADDITIONAL BOTTOMLIMIT SWITCHES MOUNTED ADJACENT SAID FIRST MENTIONED LIMIT SWITCH, AND APLURALITY OF ADDTIONAL BOTTOM STOPS MOUNTED ON SAID MEMBER, EACH OF SAIDADDITIONAL BOTTOM STOPS BEING ADJUSTABLE WITH RESPECT TO SAID MEMBER,AND AN OPERATIVE ELECTRIC CIRCUIT INCLUDING SWITCH MEANS FOR PLACING MAYAND ALL OF SAID LIMIT SWITCHES SELECTIVELY INTO OPERATIVE RELATION TOSAID CIRCUIT, AND MEANS FOR RENDERING SAID SELECTED LIMIT SWITCHESOPERATIVE IN ANY SEQUENCE RESPONSIVE TO SUCCESSIVE STROKES OF SAID RAMTO PROVIDE A CYCLE OF OPERATION WHEREIN THE DOWNWARD MOVEMENT OF SAIDRAM IS STOPPED AT DIFFERENT POINTS ON SUCCESSIVE STROKES IN SAID CYCLE,WHEREBY ALL OF SAID BOTTOM STOPS MAY BE ADJACENT AS A UNIT TO COMPENSATEFOR VARIATIONS IN THICKNESS OF THE MATERIAL BEING OPERATED UPON, WITHOUTDISTURBING THE SETTINGS OF SAID STOPS IN RELATION TO EACH OTHER.